1. Field of the Invention
The present invention relates to a method of manufacturing a solid acid catalyst, and more specifically to a method of manufacturing a zeolite catalyst.
2. Description of the Related Art
Catalytic material may be used in various applications. One application is to decompose nitrogen oxide (NOx) into nitrogen and oxygen. The nitrogen oxide (NOx) generated in an internal-combustion engine is decomposed by the catalyst before exhaust gas containing the nitrogen oxide is discharged to the atmosphere.
A zeolite of ZSM-5 is well known as a highly efficient solid acid catalyst. ZSM-5 has a catalytic function to promote chemical reactions such as isomerization of hydrocarbons, alkylation of hydrocarbons, and catalytic cracking.
However, conventional ZSM-5 has several problems. For example, the raw material used to manufacture ZSM-5 is relatively expensive and the manufacturing process is complicated such that ZSM-5 becomes expensive and the application thereof is therefore generally limited to specific fields such as automotive applications.
In order to solve the above problems, one method of manufacturing a ZSM-5 solid acid catalyst has been developed, as disclosed in Patent Document JP, H06-182212, A.
JP, H06-182212, A discloses the use of coal ash as a raw material for a distinct reduction of material cost. However, the reaction time thereof is on the order of 36 hours long, resulting in low productivity and high energy costs for manufacturing.
The ZSM-5 catalyst obtained has grains of a very small diameter so that the number of effective pores is reduced. A filtration process for liquid-solid separation at the final step of manufacturing takes a relatively long time. When the ZSM-5 is fabricated into a honeycomb structure to be utilized in an actual vapor or liquid process, the binder degrades the performance of the catalyst.
The amount of industrial waste such as from insulators, optical fiber, silicon dioxide fine powder (white soot) produced by manufacturing of the optical fiber with the soot method, and tip material produced in the pulling process of the optical fiber, has been recently increasing. It is assumed that the amount of the industrial waste thereof will continue to increase. There is no existing practical processing method known and the cost of the current process is expensive.